Ship-detector.



F. S. LONG;

SHIP DETECTOR.

APPLICATION FILED FEB. 21, 1908. 948,424. 7. Patented Feb. 8, 1910.

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I. S. LONG.

SHIP DETECTOR. APPLICATION FILED FEB. 21, 190B. 948,424. Patented Feb.8,1910.

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P. S. LONG. SHIP DETECTOR. APPLICATION FILED FEB. 21, 190B.

, Patented Feb. 8, 1910. 3 SHEETS-SHEET 3.

U Ill I||| lllln l UNITED STATES. PATENT OFFICE.

FRANK. S. LONG, OF-THE' UNITED STATES ARMY.

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Specification of Letters Patent.

Patented Feb. 8, 1910.

Application filed February 21, 1908. Serial No. 417,198;

To all whomtt may concern:

Be it known that I, FRANK S. Lone, a citizen of the United States ofAmerica, and a captain in the U. S. Army, stationed at Fort Andrews, inthe town of Hull,

Plymouth county, State of Massachusetts,

have invented certain new and useful Improvements 1n Ship-Detectors, ofwhich the following is a specification.

In defending a coast by means of shore fortifications from an attack bythe Warships of an enemy it is essential that the positions exact pointdetermined upon.

result depends upon the accurate p otting of the position of thevessels, the range and tion's when the vessels cannot be, thus seenazimuth of which is first determined by suitablelposition finders.

ile, the system works very satisfactorily under ordinary conditions whenthe vessels can be clearly seen by the observers through the telescopesforming a part of the position finding instruments, it has thegreatdisadvantage that under abnormal condithe entire system .is put out ofcommission. It is evident that these abnormal conditions frequentlyoccur as, for instance, in foggy or hazy weather, or in the night timewhen the shore illuminating lights and searchlights are weak ordefective. It is obvious, therefore, that some provision should be madeby which the location {of the vessels of an enemy may be determined evenunder these adverse conditions and it is the object of the presentinvention to provide a means whereby this most important defect inthepresent system of coast defense may be entirely overcome. v

The invention consists in providing the waterarea in front of a systemof coast defense with a plurality of groups of devices the position ofeach of which is accurately lotted on a chart to be placed-upon theorinary plotting board used in the fire commander s station. Y

Eachof the devices is electrically connect-f ed to audible and visualsignals and indicators at the fire commanders station and each device isprovided with an apparatus which is adapted to operate said indicatorswhenever a disturbing element enters its immediate'vicinity, suchapparatus including a device, such as a magnetic needle, which will bemoved from its normal position whenever any object such as a vessel,containing amass of metal, enters its sphere of magnetic influence andthus close an electric circuit to cause the operation-of the indicatoron shore or at some other distant point.

The invention further consists in certain novel features of constructionand arrangement of parts which will bev readily understood by referenceto the description of the drawings and to the claims hereinafter ven. Ofthe drawings: Figure '1 represents a vertical section through a art of acoast fortified for defense from e vessels of an plied thereto. Fig. 2represents a plan of a chart indicating the positions of the firecommanders station, the shore batteries and the various detectors in thechannel adjacent to said batteries. Fig. 3 represents 'a dia-' grammaticview showing a detector in vertical section, its indicator device inelevation, and the electric connections between the two. Fig. 4represents a side elevation. of said indicator. Fig. 5 represents avertical section of the same, the cutting plane being on line 55 on Fig.3. Fig. 6 represents an elevation of an indicator panel containing theindicators for an entire group of detectors. Fig. 7 represents anenlarged view of the cam-operating mechanism. Fig. 8 represents asection of the same, the cuttin plane being on line 8-8 on Fig. 7,

enemy, showing the present invention apan Fig. 9 represents a sectionthrough the a system forthe defense of a coast. This station-10 isconnected by means of a plurality of cables 11 with junction boxes 12lying upon the bottom of a ship channel which it is desired to defend.From each of the junction boxes 12 radiate a plurality of double'corecables 13 at the end of each of which is located a receptacle 14 whichis provided with a suitable weight 15 which retains. the receptacle atthe bottom of the channel and prevents its displacement when oncelocated. The top of the receptacle 14 is closed by means of a suitablecover 16 which hermetically seals the receptacle. Within the interior ofthereceptacle 14 is a suitable frame 17 havin bearings 18 in which ismounted a revo uble shaft 19 to which is secured a cam member 20.

Freely revoluble u on said shaft 19 is a ratchet wheel 21 WlllCll whenused in one direction is adapted to engage a springoperated pawl 22pivoted to the cam 20 to move said cam 20 and shaft 19 about the axis ofsaid shaft while at the same time said ratchet wheel'is free to be movedin the opposite direction without afiectingthe rotation of said shaft19. To the ratchet wheel 21 is secured a pinion 23 the teeth of whichengage with a segment of a gear 24, pivoted at 25 and provided with anarm 26, which segment 24 is adapted to be moved about its pivot 25 bymeans ofthe solenoid 27 acting upon the arm 26 thus actuating the pinion23 to ,cause said ratchet wheel 21 to be out affecting the operation 'ofthe pawl 22.

Interposed between the segment 24 and the frame 17 is a spring 28'whichcauses the segment 24 to be moved in the opposite direction when thesolenoid 27 becomes demagnetized, this movement caused by the retractionof the. spring 28 causing the ratchet wheel 21 to contact with the pawl22 and move the cam 20 through an arc of 180. The movement of thesegment 24 is limited in either direction by means of the stops 29 and30 on either side thereof. lmmedlatel above the shaft 19 in bearings31-32 is mounted a reciprocating rod 33 the-lower end of which isprovided with a revoluble truck 34 adapted to engage with 1 and beactuated by the cam 20, the weight of said reciprocating rod beingsuflicient to mamtain an engagement between the truck 34 and the cam20at all times. The upper end of the reciprocating rod 33 is tapered asindicated at 35andextends into a conical socket 36 to which is secured amagnetic needle 37, said needle being free to move in'azimuth about thepointed end 35 of said recipro eating rodwhile at; the same time'it maydip or tilt freely on said pointed end.

In a bearing 38 forming a part of an insulating member 39 within saidrecep tacle 14 is a. depending rod 40 in ax al line with thereciprocating rod 33 and mounted upon this rod 40 so as to be free toinove horizontally about the axis thereof is a member 41 extending inopposite directions with the surface of the loop 43. At the same timethe loops 4243 are so constructed that they are of equal weight so thatthe member 41 is perfectly balanced. The upper ends of the loops 4243are each provided with a V-shaped centering member 44 which is adaptedto accurately center the needle 37 when the needle is lifted by means ofthe cam 20 and brought into contact with the V shaped member 44, thusbringing the needle 37 and member 41 into the same plane. The inner faceof the loop 42 is provided with a lining of carbon which prevents injuryto the metal loop when contact is made between'the same and the needle37.

It is ,obvious from the foregoing description that when a current ofelectricity tact with the arm 26 of the segment 24 and. cause saidsegment to be moved to the right of Fig.. 3 without affecting theposition ofa the cam 20. When said segment has reached the extreme ofits movement in that direction and comes into contact with the stop 30and the solenoid 27 has become demagnetized the spring 28 will act uponsaid segment to return it to its normal position,

thus effecting a movement of the cam 20 about the axis of the shaft 19through an arc of 180, thus lifting the reciprocating rod 33 and causingthe needle 37 to come into contact with and become centered by theV-shaped member 44, thus lifting the member 41 slightly above the head46 of said depending rod 40. This lifting of the member 41 away from thehead 46 reduces the friction between these two members so that theneedle 37 with its centering member 41is .more freely moved about theaxis of said reciprocating rod 33 ermitting it to find its true magneticnort As soon as this position has been fully determined and the needlecomes to a rest, another current of electricity .is passed through thesolenoid 27 and the operation of the segment 24 is repeated, causing thecam 20 to againbe moved through an arc of 180 to its original position,thereby permitting the reciproeating member 33 with its needle 37 tofall by its own weight, the member 41 also falling at the same timeuntil it comes into contact with the head 46 which limits its movement,while the needle continues to drop until-it has reached a positionsubstantially central in the loops 4243. When in this position it isobvious that whenever any mass of metal such as a warship enters the inone direction or the other orbe' tilted about the pointed end 35, thismovement of the needle causing a contact to be made between the northpole of the-needle and the interior face of the loop 42, thus making acompleteelectric circ iit. I

The upper end ofthe depending rod 40 is provided with a suitable bindingpost 47 from which extends a wire 48 to the ground 49. The shaft'l9 isconnected in circuit by a wire 50 to a switch 51 located at some distantpoint, as, for instance, in the lite cornmanders station 10 on the shoreof the coast which it is desired to defend.

From the switch 51 extends aiwire 52 connecting said switch with asuitable battery 53 said battery being also connected by means of aconductor 54 to a suitable switch 55 which in turn is connected by meansof a conductor 56 to a suitable rheostat 57 adapted to regulate theamount of current passing through said conductor. This rheostat 57 isconnected by means of the conductor 58 to a tripper switch 59 connectedby means of a conductor60 to a switch 61 from which a conductor 62extends to a ground 63. From the .wire 50 branches a wire 64 extendingto the solenoid .27, the opposite end of the coil of which is connectedby means of a wire conductor 65 to the switch 66, this switchbeing'conn'ected by means of the conductor 67 and branch conductor 68,to the tripper switch59 and thearmature magnet 69, the opposite end ofthe coil of which is connected by means of theconductor 70 to the switch61 or through the conductor 62 to the ground 63.

A current of electricity passing through the magnet 69 is adapted tooperate a pivoted armature 71, the opposite end of which extends overthe tripper switch 59 which is pivoted 'at 72and is moved about saidpivot by means of a spring 73 when the pivoted armature7l releases thesame. This movement of the tripper switch'59 will break the circuitbetween the switch 66 and the rheostat 57 and at the same time causea-circuit to be made between the conductor 60 and the conductor 56.

Connected with the conductor 54 is a conductor .7 4 which connects withthe conductor 56 and contains within the circuit an audible signal 75such as a bell, and a visual signal, such as an electric light or lamp76. The

conductors 50' and 65 indicated' in Fig. 3;

form the double core cables 13 interposed between the receptacles 14 andthe junction box 12 and extend from the junction box 12 to the firecommanders" station 10 in the form of a multiple cable 11, whichcontains all the double core cables from-. a single g pl j The'va'riousswitches shown .inFig. 3 are all mounted upon a block 77 one of which isprovided for each receptacle 14 in use. The blocks for every group 78 ofdetectors 14 are mounted -together upon a suitable panel 79 and each ofthe blocks are provided with a. number or other designating character 80to indicate the particular receptacle -wi th which it is connected. Inlike manner the panels containing the various blocks 77 are providedwith suitable designatingcharacters such as A, B, G, 1), etc. In theoperation of the invention the normal position of the cam 20 has itslongest axis downward with the reciprocating member 33 in its lowestposition, the needle 37 also being in its lowest position while themember 41 rests upon the flanged head '46 with the ends of the needle 37in the center of the loops 42-43. This is the normal position of thevarious parts contained within the receptacle 14 at all times until theapproach of an enemy. When it has been discovered that an enemy is inthe vicinity of the coast which is to be defended the 'operator withinthe fire commanders station 10 first closes the switches 51 and 55leaving the switches 61, 66, and 81 open, and the, tripping switch 59locked by means of the armature lever 71. When the switches 5155 are inthis position the adjusting circuit may be made by means of the switch66 which is normally open but' when it is desired to adjust the needle37 and the centering member 41 the switch 66 will be closed and acurrent will thereby be allowed to flow from the battery 53 through theconductor 65 to the solenoid 27, thus efiecting a movement of thesegment 24 and causing the cam 20 to be moved into] the position "shownin Fig. 3, as has been hereinbefore described. As soon as the switch 66has been closed sufiiciently long to permit the current to energize thesolenoid 27 it is immediately opened and as soon as sutlicient time haselapsed to permit the needle 37 and member 41 to come to rest at thetrue magnetic north the switch is again closed for a sufficient lengthof tune to again energize the solenoid 27 and cause the cam 20 to bereturned to its normal -pos1 t1on as heretofore described.

The apparatus is then in condition to serve as a detector upon the nearapproach of an warship. or any other object capable of e fect-ing amovement of the needle 37. In

order to indicate the approach of such an ob- "12 ject'within the sphereof influence of said magnetic needle, 1t is-desirable that at somedistant point such as the fire commanders station, some visual andaudible signal should be, given to indicate the position of suchanaobject and in order to do this it is necessary to open the switch 55to allow the currentpassing from the battery 53 to ass through the hellor other audible signa 75 and the electric lamp or other visual signal 76, the switches 5161 being closed under these conditions, while theswitch 66 remains open, the switch 81 closed and the tripping switch 59remains locked by means of the pivoted armature 71. are in thiscondition the whole apparatus is ready to operate so that as soon as avessel or other object capable of effecting a movement of the needle 37approaches'within the sphere of magnetic influence the needle will beaffected thereby to cause its movement about its support 35 so that thenorth pole thereof will either be tilted vertically or movedhorizontally until it comes into contact with thecarbon face of the loop42'to complete the circuit and as soon as this circuit is thus completeda current of electricity passes through the magnet 69 and.energizes thisso that the pivoted armature 71 is operated upon to release the trippingswitch 59 which when thus rele ased is operated upon by the spring 73 tobreak the circuit between the rheostat 57 and the conductor 67 and makesa connection between the conductor 60 and the conductor 56. When thisconnection has been made the magnet 69 and rheostat 57 is cutout and thecurrent passes directly from the switch61 through the circuitscontaining theaudible signal 75 and the visual signal 76 and causes bothto operate. Both of these signals remain in operation until the operatorcomes to the panel and determines what block and'what group is inoperation. When he has determined what particular detector has beenoperated by means of the designating characters on the panel and theblock on said panel he then opens the switch 51 which cuts out theapparatus and causes a cessation of the two signals. The operator .thenwaits until the disturbing influence has moved away from the detectorwhich is determined by suitable tests of the apparatus and as soon as hediscovers that this is the fact he again opens the switch 61, looks thetripping switch 59 by means of the armature 71, and then closes theswitch.51. When this has been accomplished the'indicator is again incondition to repeat the operation as has been heretofore described. Assoon as the operator hears the signal and by means of the visual signaldetermines which detector has operated, he determines the group.designated and .the block designated and sends this data to the plottinroom where it. is plotted upon the usual p otti-ng board.

The accurate location of each of the detectors properly designated bynumbers or other characters and the exact location of each of the groupsare plotted upon the ordinar'y plottlng board so thatwhen any one ofthedetectors is operated and the information is sent to the-plotting roomthat a designated detector of a designated group has been operated, theplotting room detail When the switches as well as its speed.

of the bottom of the channel.

can accurately locate the position of the disturbing element and securethe exact range and azimuth from the gun by the usual methods to be sentto the gun commanderin order that he may direct his fire at theparticular locality in which the disturbing element may be at that timelocated.

Owing to the arrangement of the various detectors of groups at adesignated distance from each other lengthwise of the channel, whichdistance is accurately known in the plotting room the exact speed of avessel passing through the channel may be readily determined by notinthe exact time that a detector is operated %y such a vessel in the firstgroup and then denoting the exact time that the same vessel operates adetector in the second group and making the necessary calculationstherefor. It is obvious also that by accurately determining whichdetector of each group is operated in this manner by a opasslng vesseland drawing a line on the' plotting board connectin the detectors thusoperated that the exact direction of the vessel in the channel may beaccurately determined It is obvious'that in locating the various signalsit is necessary that the weight 15 should be'suflicient to alwaysmaintain the operating parts in a perfectly horizontalposition andprevent the receptacle and the parts contained therein from beingdisplaced in any manner regardless of the condition In practice it isintended that the receptacles should be suitably anchored in a bed ofconcrete which would prevent the receptacles from being disturbed underany ordinary conditions. Should, however, the ,enemy attempt to drag thechannel and the dragging devices come into contact either with thereceptacles or the cables connected therewith the receptacles would bebodily moved and the physical disturbance thereof which ensues wouldcause a movement of the needle 37 and an electric contact to be madewhich would indicate the presence of some disturbing influence at thatparticular point indicated on the block and panel. It is also obviousthat the apparatus herein described is particularly adapted for use todisclose the presence of submarine vessels of an enemy, the presence ofwhich could not be readily determined from the shore fortifications andif groups of these characters were placed in advance of the outer minefield the approach of the submarine vessels for the purpose of explodingthe mines or cutting them loose would be discovered befoi ethey hadreached the mine field and were able to do any damage. When these outerdetectors are disturbed by the presence of submarines or other boatsattempting to destroy the mine field and their location is accuratelydesignated to the shore fortifications, fire can be opened on them bymortars or other high angle fire which would be liable to put themout ofcommission or make their position untenable.

Not only may the Vessels of an enemy be l cated by this apparatus whenin the water area adjacent to a fortification, which under normalconditions would be in view of the observers of the defense, but thesevessels could also be locatedwhen in waters or anchorages concealed fromthese observers. It'is obvious that when these vessels are thus locatedby this apparatus their position would soon be made untenable by mortarsand other high an le ordnance, the range and azimuth being from the firecommanders station where the indicators connected with the detectors arelocated.

Anothergreat advantage of the apparatus is that at night the location ofan enemy may be accurately determined without the use of the shoreilluminating and searchlights which betray to the enemy the position ofthe defense. It is quite obvious that the same devices may be utilizedon land. with the detectors buried at certain points in advance of afortification to indicate the presence of artillery.

Another purpose for which the device could be utilized is to designatedangerous shoals or submerged reefs by having detectors placed inadvance of such dangerous places and connected to audible or visualsignals or both, located upon such dangerous places or adjacent thereto,which would be operated by the near approach of a vessel and thus warnthe shipmaster of approaching danger; Y

Having thus described my invention, I claim:

1. Thecombination of a device including a magnetically operated circuitcloser normally openadapted' to be operated to close said circuitwithout betraying its location by the presence in its immediate vicinityof a mass of metal; an apparatus at a distant point therefrom adapted toindicate such presence in the vicinity of said device; and meansinterposed between said device and apparatus whereby the latter will beactuated by the operation of the former.

2. The cobmination of a device includinga magnetically operated circuitcloser normally open adapted to. be operated -to close said circuitwithout betraying its location by the presence in its immediate vicinityof a mass of metal; an apparatusat a distant point therefrom adapted toindicate such presence in the vicinity of said device; and an electriccircuit interposed between said device and apparatus whereby the latterwill be actuated by the operation of the former.

3. The combination of a device adapted to be operated by the presence inits immediate vicinity of a mass of metal; an apparatus at rnished thegun commander.

- immediate vicinity;

a distant point therefrom adapted to indicate suchpresence in thevicinity of said device; means interposed between said device andapparatus whereby the .latter will be actuated by the operation of theformer;

and means for retaining said device in inoperative position untilreleased. 4. The combination of a device including a'movable memberadapted to be operated by the presencein, its immediate vicinity of amass'of metal; an electric lamp at a distant point therefrom; mechanismfor center- 1n a distant point for operating said centering mechanism;and means including acontact member interposed between said device and.electric lamp whereby the latter will be lighted by the engagement ofsaid movable member and said contact member.

5. The combination of a device including a movable member adapted to beoperated by the presence inits immediate vicinity of a mas of metal; anelectric lamp and a ism for centering said movable member; means locatedat a distant point for operat said movable member; means located at bellat a distantpoint therefrom; mechan ing said centering mechanism; andmeans including a contact member interposed between sa1d device andelectric lamp .and bell whereby the lamp will be lighted and the bellrung .by the engagement of said movable member and said contact member.

6. The combination of a device including a magnetically operated circuitcloser normally open adapted to be operated to close said circuit by thepresence'in its immediate vicinity of a mass of metal without betrayingthe location of said device; anindicatorat a distant point therefrom;means interposed between said device and indicator whereby the latterwill be actuated by the operation of the former; and a switch adjacent-to said indicator adapted to put said device in and outof commission.

7. The combination of a submerged device including a movable memberadapted to be operated by the presence of a vessel in its an' indicatorat a distant point therefrom; a contact member coacting with saidmovable member; means at a distant point for positioning said cont-actmember; and a connection between said in-- dicator and submerged devicewhereby any operation of said submerged device that causes? anengagement between said contact member and said movable member willeffect an operation of said indicator and cause a fact to be indicatedthereby. r

' 8. The combination of a submerged device including a movable memberadapted to be.

operated by the presence of a vessel in its immediate vicinity; anelectric lamp at a distant point therefrom; a contact memberco-actingwith said movable member; means at a distant point forpositioning said contact member; and a connection between said electriclamp and submerged device whereby any operation of said submerged devicethat causes an engagement between said contact member and movable memberwill effect an operation of said indicator and ,cause a fact to beindicated thereby.

9. The combination of a submerged deviceincluding a movable memberadapted to be 10 operated by the presence of a vessel in its immediatevicinity; a visual signal at a distant point-therefrom; a contact memberco-acting with Said movable member; means at a distant point forpositioning said con-. tact member; and a connection between said.visual signal and submerged device whereby any operation of saidsubmerged device that causes an engagement between said con tactmemberand movable member will effect an operation of said indicator and causea fact to be indicated thereby.

10. The combination of a submerged receptacle; a magnetic needletherein; an indicator removed from said receptacle; a contact member oneach side of sa1d needle; means at a distant point for positioning saidcontact members; an electric circuit between said indicator andreceptacle; and mechanism actuated by said needle when in engagementwith either contact member adapted to energize said indicator. I

11. The combination of a submergedreceptacle; a magnetic needle therein;an indicator including both a visual and an audible signal removed fromsaid receptacle; a

contact member on each side ofsaid needle; means at a distant point forpositioning sa1d contact members; and mechanism actuated by said needlewhen in engagement with elther of said contact membersadapted toenergize said indicator.

12. The combination of a submerged re ceptacle; a magnetic needletherein; an indicator including botha visual and an audiblesignal'removed from said receptacle; a contact member on each side ofsaid needle; means at a distant point for positioning said ontactmembers; an electric circuit between s id indicator and receptacle;mechanism actuated by said needle when in engagement with either of saidcontact members to energize said indicator; and means in said electriccircuit for cutting out said needle until its operation is desired.

13. The combination of a plurality of submerged devices each containinga mag netically operated circuit closer normally open adapted to beoperated to close said clrcuit by the presence of a vessel in itsimmediate vicinity without betraying its location; an indicator at adistant point provided with a separate signal for each device; and anelectric circuit normally open interposed between said devices and saidindi- I cator adapted to operate a diflerent-signal submerged deviceseach containing -for each device whenever such'device is set inoperation.

14. The combination of a plurality of a magnetically operated circuitcloser normally open adapted to be operated to close said circuit by thepresence of a vessel in its immediate vicinity without betraying itslocation; an indicator at a distant point provided with a separatesignal for each device; an electric circuit interposed between saiddevices and said indicator adapted to opxerate a differentsignal foreach device w enever such device is set in o eration; and means forcutting out said devlces until their operation is required.

i 15. The combinatlon with a submerged receptacle of a' magnetic needlecontained therein; an indicator;.an electric circuit between' saidindicator and needle; a contact member in the path of said needle oneach side thereof; and means for normally locating said contacts inpositions equidistant from said needle when at rest so that the electriccircuit will be closed by any movement of said needle due to theaction'thereon of a mass of metal within its sphere of magneticinfluence.

16. The combination of a magnetic needle; contact memberstherefor; adevice for normally centering said needle between said contact members;means located at a distant I point for controlling said device; anindicator; an electric circuit between said indiator and needle normallyopen; and means for closin said circuit by the movement of said need edue 'to the action thereon of a mass of metal within its sphere ofmagnetic influence.

17. The combination of a magnetic nee-. dle; a member adapted totemporarily rest on said needle; means for separating said member andneedle; an indicator; an electric circuit between said indicator andneedle normall open; and means for closing said circuit by the movementof said needle due to the action thereon of a mass of metal within itssphere of magnetic influence.

18. The combination of a magnetic needle; a member adapted totemporarily rest on said needle; a revoluble cam for separating saidmember therefrom; an indicator; an electric circuit between saidindicator and needle normally open; and means. for closing said circuitby the movement of said needle due to the action thereon of a mass ofmetal within its sphere of magnetic influence. i

19. The combination with a submerged receptacle ofa magnetic needlecontained therein; a vertical support therefor; a revoluble cam beneathsaid support; means for actuating said cam to alternately raise andlower sa1d support; an indicator; an electric'circuit between saidneedle and indi to alternately raise and lower said support;

netic influence.

an indicator; an. electric circuit between said needle and indicatornormally open;

and means for' closing said circuit by the movement of said needle dueto the action' thereon of a mass of metal within itssphere of magneticinfluence. 21. The combination of a magnetic needle; a vertical supporttherefor; a revolu-' ble cam; a solenoid for actuating said cam toalternately raise and lower said support; means located at a distantpoint adapted to energize said solenoid; an indicator; an'electric'circuit between said needle and indicator normally open; and means forclosing said circuit by the movement of said needle due to the actionthereon of a mass of metal within its sphere of mag- 22. The combinationof a magnetic needle; a vertical su port therefor; a member freelyrevoluble a bove said needle; a revoluble cam; means for actuating saidcam to alternately raise and lower the needle and said member; means forlimiting the downward movementof said member; an indicator; an electriccircuit between said needle and indicator normall open; and means for.closin said circuit by the movement of said nee le-due to the actionthereon of a mass of metalin its sphere of magnetic influence. v

23. The combination of a magnetic needle; a vertical support therefor; amember freely revoluble above said needle; a loop depending from eitherend of said member and surrounding said needle; a revoluble m; means foractuating said cam to alt rnately raise and lower said support; anindicator; an electric circuit between said needle and indicatornormally open; and

means for closin said circuit by the move-.

, ment of said nee le due to the action thereon of a mass of metal inits sphere of mag netic influence.

24. The combination of a magnetic needle; a vertical support therefor; amember freelyme'voluble above said needle; a loop depending from eitherend of said member and surrounding said needle, the loop at the northpole of said needle being smaller than the other; a revoluble cam; meansfor actuatingsaidcam to alternately raise and lowersaid support; anindicator; an electric circuit between said needle and indicatornormally open; and means for closing said circuit -'by' the movement ofsaid needle due to the action thereon of a mass of metal in its sphereof magnetic influence. I

25. The combination of'a magnetic neefreely revoluble above sa1 needle;a loop depending from either en ,of said member and surrounding saidneedle, the loop at the north pole of said needle being smaller than theother; carbon lining to the smaller'loop; a revoluble cam; means foractuating said cam to alternately raise and lower said support; anindicator; an electric circuit between said needle and indie ,dle; avertical support tlfigefor; a member cator normally open; and means forclosing said circuit by the movement-of said needle due to the actionthereon of a mass of metal in its sphere of magnetic influence.

26. The combination of a magnetic needle; a vertical support therefor; amember freely revoluble above said needle; a loop depending from eitherend of rounding said needle, the loop at the north pole of said needlebeing smaller than the other; a carbon lining to the smaller loop; aninverted Vshaped needle. centering device in each loop; a revoluble cam;means for actuating said cam to alternately raise and lower saidsupport; an indicator; an electric circuit between said needle-andindicator normally. open; and means for closing said circuit by themovement of said needle due to the action thereon of a mass of metal inits sphere of magnetic influence.

27. The combination of a magnetic needle; a vertical support therefor; amember freely revoluble above said needle; a loop depending from eitherend of said member and surrounding said. needle, the loop at the northpole of said needle being smaller than the said member and surother; acarbon lining to the smaller loop; a needle centering device for eachloop; a revoluble cam; means for actuating'said cam to alternately raiseand lower said support; an

indicator; an electric clrcuit between said needle and indicatornormally open; and means for closing said circuit/by the movement ofsaid needle due to the action thereon of a mass of metal in its sphereof mag- .netic influence.

28. The combination of a magnetic needle; a vertical support therefor; aheaded sup port above and in axial line with said needle support; amember looselymounted thereon above said needle; a loop depending fromeither end'of said'member and surrounding said needle, the loop-at thenorth pole of I said needle being smaller than. the other; a carbonlining to the smaller loop; a revoluble cam; means for actuating saidcam to alternately raise and lower said support; an indicator; anelectric circuit between said needleand indicator nbrmally open; andmeans for closing said circuit by the l movementof said. needle due tothe action thereon of a mass of metal in its sphere of magneticinfluence.

29. The combination of a magnetic needle; a vertical support therefor; aheaded support above and in axial line with said needle support; amember loosely mounted thereon above said needle; a loop at each end ofsaid member surrounding said nee-' dle; a revoluble cam; means foractuating said cam to alternately raise and lower said support; anindicator; an electric circuit between said needle and indicatornormally open; and means for closing. said circuit .by the movement ofsaid needle due to the action thereon of a mass of metal in its sphereof magnetic influence.

30. The combination of a magnetic needle; a vertical support therefor; acam for alternately raislngand lowering said support and needle; amember freely revoluble reely revoluble above said needle; means 35 orbringing said member and needle into the same vertical plane; anindicator; an electric circuitbetween said needle and in dicatornormally open; and means for closing said circuit by the movement ofsaid needle due to the action thereon of a mass of metal within itssphere of magnetic influence.

32. The combination of a magnetic needle; a vertical support therefor; acam for alternately raising and lowering said support and needle; aspring-pressed awl on said cam; a ratchet whee with WhlCll said pawl isadapted to engage loosely mounted onthe shaft of said cam; means for.alternately moving said wheel in o posite directions;

an ind cator; an electric clrcuit between said needle and indicatornormally open; and means for closing-said circuit by the move ment ofsaid needle due to the action thereon of a mass of metal withinitssphere of magnetic influence.

33; The combination of a magnetic needle; a Vertical support therefor; acam :for

- alternately raising and lowering said support and. needle; aspring-pressed awl on said cam; a ratchetv wheel with WhlCll said pawlis adapted to engageloosely mounted on the shaft of said cam; a earsecured to said ratchet wheel; a pivot gear; segment meshing therewith;,means for moving said .ing therewith; a solenoi gear segmentalternately in opposite directions; an indicator; an electric circuitbepawl is adapted to engage loosely mounted on the shaft of said cam; acar secured to said ratchet wheel; a pivote (gear segment meshingtherewith; a solenoi adapted to move said segment in one direction; aspring 1 adapted to move said segment in the opposite direction;an'indicator; an electric circuit between said needle and indicatornormally open; and means'for closing said circuit-by the movement ofsaidneedle due to the action thereon of a mass of metal within itssphere of magnetic influence. 4

. 35. The combination of amagnetic needle; a vertical support therefor;a cam for alternately raising and lowerin and needle; a spring-pressecam; a. ratchet wheel with which said pawl is adapted to engage looselymounted on the shaft of said cam; a ear secured to said ratchet wheel; apivote gear segment mesh adapted to move said segment in one direction;a spring adapted to move said segment in the opposite direction; stopsto hmit the movement of said segment in each direction; .an indicator;an electric circuit between said needle and indicator normally open; andmeans a for closing said circuit by the movement of said needle due tothe action thereon of a mass of metal within its sphere of magneticinfluence. I

36. The combination with a detector consisting of a submergedhermetically sealed receptacle containing a normally open cir-. cuitcloser including a magnetic needle 7 adapted to close said circuit whenaffected by the presenceoof a mass of metal withinits sphere of magneticinfluence without betraymg the location of said detector; of anindicator in said circuit provided with a visual and audible signaladapted to beoperated by the closing of said circuit.

37. The combination with a detector rovided with a magnetic needleadapte to close. an electric circuit when affected by the presence of amass of metal within its sphere of magnetic influence; of a tripperswitch; means for normally locking said switch; a signal deviceconnected with said switch; and means operable by the closure of saidcircuit to release said tripper switch and permit 1t to close thecircuit to said signal device and effect its operation.

'38. The combination with a detector rovided with a magnetic needle adate to close an electric circuit when alfeote by the presence of a massof metal within its sphere of magnetic influence; of a tripper switch; A

a pivoted lever for locking said tripper switch; a signal device, and anelectro-magnet adapted to operate said lever to release said switch andpermit it to close the circuit to said signal device and efi'ect itsoperation.

'39. The combination of a submerged device including a magneticallyoperated circuit closer 'normall open adapted to beoperated to close saiclrcuit by the presence FRANK S. LONG.

Witnesses:

EDNA C. CLEVELAND, WALTER E. LOMBARD.

